IMAGINE A FAMILY that prides itself on its loyalty to their favorite football team. Their home is decorated with sports memorabilia. They almost never miss a home game. Sometimes, they build their family vacations around road games, especially during the playoffs. Dad is the most diehard fan in the family; he always goes to the stadium wearing a team jersey, his face painted with the team colors. Other family members are a bit less fanatic, and that’s okay — especially as the kids move out of the home to study or work in other cities.

But one thing will never be tolerated in this family: you can not become a fan of the rival team, and you’d better think twice about marrying someone who is. The unspoken message is, Do that, and you’ll be spending Thanksgiving, Christmas, and Super Bowl Sunday on your own.

This is a tongue-in-cheek example of the difference between a bounded set versus a centered set. Both can be used as ways to think about the implicit rules for membership in social groups. In a centered set, membership is defined by how closely one holds to some shared core value. Not everyone in the family need be as fanatic as Dad, but they should be drawn toward his enthusiasm as an ideal. In a bounded set, however, the emphasis is on drawing hard lines that simultaneously include and exclude. There’s a dividing line between in and out; root for the wrong team, and you’re out.

The two ways of thinking aren’t necessarily mutually exclusive; again, it’s a matter of emphasis. The distinction between bounded and centered sets has been applied to the church, perhaps most famously by a former colleague of mine, the anthropologist and missiologist Paul Hiebert. We might think of it this way. Churches have core theological convictions, and these imply a boundary; to be a member here, you have to believe what we believe. But how is the cohesion of the community maintained?

One way is to emphasize the teaching, preaching, and embodiment of core convictions: This is what we believe, and what we believe defines who we are striving to be. But it’s possible to emphasize the boundaries instead; one gets the sense that what matters most is to keep out the riffraff.

Which of these, then, is the case in 2 John?

WITH THEIR NEW but false ideas about Jesus, the secessionists had crossed the line into heresy. Having failed to convince others in John’s community to come around to their way of thinking, they began taking their message to other communities.

I imagine the situation as being somewhat alarming to John. Given the fatherly affection we see throughout 1 John, the threat of other communities being undermined and hurt by the secessionists’ false teaching must have awakened his protective instincts. That’s the reason for the letter we know as 2 John, in which the apostle, feeling the weight of responsibility, exercises his full authority. He draws a firm boundary against those who have “run ahead,” against those who have gone too far with their teaching:

Anyone who runs ahead and does not continue in the teaching of Christ does not have God; whoever continues in the teaching has both the Father and the Son. If anyone comes to you and does not bring this teaching, do not take them into your house or welcome them. Anyone who welcomes them shares in their wicked work. (2 John 9-11, NIV)

Don’t take them into your house, John says. Don’t welcome them. These are striking words, especially given how much the virtue of hospitality was needed and valued in the early church (indeed, as we’ll see shortly, the matter of hospitality will become a central issue in 3 John). Moreover, John goes as far as to say that anyone who doesn’t listen to him and takes the secessionists into their home is essentially sharing in their wickedness. Is John therefore saying that anyone who invites an out-of-town heretic in for a cup of coffee becomes a heretic too?

Again, we have to try to read his words against the background of his context rather than ours, a context in which the church was a close-knit group that met in homes, did life together, and had no Bible to refer to should some theological controversy arise. For John to prohibit believers from taking these heretics into their homes, heretics who probably thought of themselves as Christians needing to educate the ignorant, may have been tantamount to saying, “Don’t take them into your church.”

If I try to imagine what John would say in a more contemporary context, it might go something like this. He’s not telling people to stand at the church door on Sunday morning to screen out heretics: What do you believe about Jesus, ma’am? And you, sir, what do you believe about Jesus? Okay, ma’am, you pass. Welcome, come right in! But you, sir? Sorry, you’re not welcome here.

Rather, as I’ve suggested before, translated into our social and historical context, I think John is saying, Don’t let these people have the pulpit. Don’t give them a platform to spread their heretical ideas. John says what he says, in the way that he says it, because the boundaries between welcoming the secessionists into their homes, welcoming them into the church, and giving them a platform were fuzzy at best.

So yes, John is taking a hard line, setting a clear boundary. On the one hand, his readers hold to the teaching of and about Jesus, the true teaching that’s been passed on by the apostles. They are therefore “in.” On the other hand, however, those who have innovated their way into heresy are to be kept out.

That may sound harsh, and in some ways it is. But John’s world was different from ours, and his role and status as the Elder, as an apostle, were unique. It was up to him to set boundaries in order to protect the core convictions of a movement that was still vulnerable, still in its infancy.

What about today? We still need to hold the emphases of both bounded and centered sets together. To begin with, we must know and cling to our core convictions, and that necessarily results in having at least some boundaries. That doesn’t mean turning people away at the door, but it may mean not letting just anyone have a church-sanctioned platform for their views.

But it’s also possible for boundary maintenance to take on a life of its own, keeping out the riffraff, drawing lines between “us” and “them” in a defensive and knee-jerk way that becomes increasingly distant from the commitment to embodying a gospel of love and grace.

Some lines, in other words, may need to be hard. But God’s people don’t have to be.